THE LECTURE-DEMONSTRATION AND INDIVIDUAL LABORATORY METHODS COMPARED.* I. THE LITERATURE
This article is a challenge to read critically the abundant literature on these tnuo methods of introducing students to the study of chemistry. The staled aims of the teaching of chemistry have been considered. Several studies comparing the methods at the high-school lwel have been summarized. The opinion of teachers and pnfi'ls has been considered. Our general practice has been com@red with that of one institution of higher learning in this country and the more general practice of European countries.
. . . . . .
Without any quantitative method of evaluating achievement, but merely as a matter of almost universal opinion, the idea grew up among educators that chemistry instruction must begin with individual laboratory work as an essential element. Many schools and colleges, however, have been unable to provide adequate facilities for individual experimentation in chemistry, as well as in other sciences, and this f a d has been increasingly a source of embarrassment. With the present tendency to appraise our educational practices in a scientific way we are beginning to realize that we have adopted a costly system with a background of opinion only. Perhaps the system is valuable for capable students who know they want to become chemists. It is now being questioned on many sides as a method for the masses of students finding their way to the last years of high school and the first years of college. The fact that ope successful state university (Indiana) found a system of lecture-demonstration satisfactory, while other institutions are encountering many problems in the individual laboratory method, has served as an inspiration to compare the methods. A consideration of the vast outlay of wealth in equipment for individual student experimentation should serve to make us ask whether we are receiving full value for outlay. The investment of teacher and student time should be in that method which will net the greatest return.
The Aims of Chemistry Teaching The necessity of clearly defined aims in any subject is recognized. The writer, however, has not attempted to determine what the aims in teaching first-year chemistry should be. Rather, he has brought together typical statements of these aims and attempted to point out whether or not these generally unchallenged statements inherently demand a specific method of teaching for their realization. Any attempt to evaluate teaching methods should be made in relation to the aims of the subject. The final test of ef-
* From a dissertation submitted by V. F.Payne in partial fulfilmentof the requirements for the degree of Doctor of Philosophy in the University of Kentucky. 932
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ficient teaching is the degree to which it realizes the objectives of instruction. Various groups and individuals (1)-(7) have attempted to set up the aims and objectives of first-year chemistry. While the various lists of aims in teaching chemistry here cited were intended for high-school chemistry, they may apply almost as well to first-year college chemistry. There has been no scientific background in their formulation and no general adoption of any one set of aims. Without great violence to the foregoing statements all of these aims may be listed under one of three divisions: (1) information or knowledge, (2) skill, particularly in thinking, (3) inspiration and appreciation. One writer (8) points to the "usable residue" of chemical knowledge from which every adult American should build a "chemical point of view." Another (9) points to the elusiveness of information and favors an "appreciation course" in chemistry for beginners. A group (Z),already mentioned, emphasize a scientific method of thinking as a paramount aim of beginning chemistry. Certain values and objectives of laboratory work and instruction, mentioned by Frank (5) and Smith (6), clearly imply individual laboratory work. There is nothing to indicate what portion of the total time given to chemical instruction should he devoted to individual laboratory work or at what time in the course such work should begin. It is d i c u l t to see, for the realization of the more general aims stated, any absolute necessity for individual laboratory work. C
Experimental Studies Several studies (10)-(18) have been made comparing the achievement of groups of science students taught by the individual laboratory method with that of groups taught by teacher-demonstration alone. These investigations have dealt almost exclusively with students a t the high-school level, but a number of them are worthy of comment in connection with the present study. A most valuable study by Carpenter (11), in the high-school chemistry field, is one involving thirty-four classes from twenty-three high schools in fourteen states. The large populations, the validation of tests, the wide distribution of schools, the use of many teachers and the use of modem statistical methods for computing averages, distributions, and coefficients of reliability insure confidence in this research. If Carpenter has erred a t any point in his conclusions it appears in favor of the individual laboratory method. He found a "critical ratio" of 1.27 favoring the demonstration method. While a critical ratio under three is not considered statistically significant this ratio of 1.27 indicates that there is only once chance in about four that the difference favoring the demon-
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stration method is due to errors in measurement or inadequate sampling (19). Such a difference can hardly be neglected. In contrast to these results Horton (12) found, in specific information gained and in ability to think in terms of chemistry, an even greater advantage in favor of the individual group. These first results were not considered statistically significant but Horton later devised tests measuring manipulative skills that did give significant results favoring the individual method. If Horton's work is open to criticism i t is probably in the sterility of his so-called demonstration method. He says: The manual of directions used bv the individual grona was also in the hands of the demonstration gro;p; and the teacger followed these directions without comment* and precisely as they were given. TABLE I Summary of Typical Studies Comparing the Lecture-Demonstration and Individual Laboratory Methods in High-School Chemistry Studies
Candudonr
Commeds
Wiley (lo): Three unequated groups, each of eight high-school chemistry students Anibel (13): Thirty pairs of high-schwl chemistry students for one year and seventeen pairs for a second year
Considered unfavorable t o lecture-demonstration
Differences are small. Study has a doubtful value
Knox (16): High-School Chemistry Pugh (15): High-School Chemistry
Nash and Phillips (14): Second - semester high school chemistry Carpenter (11): Thirtyfour high-school chemistry c l a s s e s f r o m twenty-threehigh schools in fourteen states Horton (12): High-schwl chemistry. Manipulative skills
-
Demonstration method is as effective as the individual laboratory, takes twothirds as much time, and costs about one-fifteenth as much as thh' laboratory Favorable t o the demonstration method Favorable to the demonstration method. The advantage continues after the compared groups are united in individual laboratory work Favorable to the "instructor" (laboratory) method Favorable to lecture-demonstration although the results were not statistically significant
A very valuable study Conservative in conclusions
Statistically significant results favorable to individual laboratory
Open to criticism on account of the sterile demonstration method used
* Italics by the present writer.
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It is hardly conceivable that such a rigidly formal demonstration method would be generally adopted, or is it one that is well designed to produce whatever values this method is capable of bringing about. Horton is, however, to be commended for his efforts to measure manipulative skills. Of the nine studies here cited, seven are either favorable to lecture demonstration in preference to individual laboratory work or they point to practically no differences. The differences between the methods are not shown to be significant statistically but the evidence is not negligible. One study has produced data that show statistically significant differences definitely favoring individual laboratory work, but in comparison with an unusual and rather sterile method of lecture-demonstration. No11 (20) has concluded that recitation or oral quiz seems a fairly profitable substitute for laboratory work but that outside reading is not. I t seems reasonable to conclude that our present extensive use of the individual laboratory method for beginners in chemistry is, to say the least, open to question. I t is imperative that proponents of the method assume the defensive if they are to justify its continuation without change. Several investigations ( Z l ) , (22), (23) have also been made in regard to the relative merits of beginning the laboratory work before the class work on a given topic and the reverse procedure. These reports refer to relatively short intervals of time between the laboratory and classroom work. They do not anticipate the possibility of having a long period of lecture demonstration precede the introduction of individual laboratory work. It seems possible to the writer that the slight differences found in the two reports favorable to "recitation first" may lead us to anticipate an advantage to a group having a prolonged period of demonstration work preceding the first individual laboratory work. At any rate, the possibility is sufficiently promising to warrant further study.
Opinion A large body of opinion (24)-(43) has grown up in the literature and is worthy of careful consideration. Some of the opinions are based on experimental studies. Other opinions which may be as valuable as these are based on a rich and observant teaching experience. Downing (24),who has directed experimental studies and who has studied all of the experimental studies in the field, is in a unique position to judge fairly. He says:
. . . . I t does seem salc to conclude that under the present conditioni or tcachine sciencr in the secund:ir~schools the dcmonstration mrthod is as effec:ive as the laboratory method in getting over to pupils the desired information and saves time and a great deal of money. . .
.
Several writers (3). (6), (33)-(36) point to inherent difficulties in individual laboratory work for beginners and to the apparent inability of many
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students to profit from such work. That the early training in laboratory practice is not efficient, or that it actually tends to develop had habits of technic is indicated by others (37), (38). It seems possible to this writer that the general student may more safely be given any values resulting from individual laboratory work but that the student who plans to continue should be protected from the poor teaching often given to large groups. Table I1 is adapted from an exhaustive study on "Teaching Science as a 'Way of Life' " (44). It indicates that the New York City high-school teachers rank the demonstration-discussion method first and individual laboratory third for giving pupils a grasp of fundamentals but the individual laboratory first and demonstration-discussionsecond for developing scientific habits in pupils in the high-school chemistry course. TABLE Il Statement by New York City Teachers Comparing Methods of Teaching High-School Chemistry Docs M o s l lo Giua Pupils Grasp
ofFundnmcnlnls PO Cent. Numbs?
Demonstration-Discussion Individual Laboratory Assigned Text Problems Combination Total
64 12 18 6 11
57.7 10.8 16.2 5.4 9.9
-
-
111
100.0
D ~ c rMosl lo D m l o p SrienliXc H o b i l s in PuPilr Number PSI C E ~ I .
21 48 9 8 6 92
22.8 52.2 9.8 8.7 6.5
100.0
C
Practice Writers (45), (46), (47) point to the more extensive use by European schools and universities of the demonstration method often to the exclusion of individual lahoratory work. Dougherty (48) has called attention to the inauguration in Princeton University of a general chemistry course dependent upon lecture demonstration without individual laboratory. Indiana University is outstanding in this country as a prominent state university which until recently introduced its beginners to chemistry by lecture demonstrations rather than by individual laboratory work. Professor Mathers (private communication) commented as follows on their experience: Our system of lecture demonstration method for freshman chemistry is of German origin. The bead of this department was educated in Germany and he liked their method. We certainly must admit that i t has been a success over there. Personally I think that it saves enough time to be worth while. More can be learned than is possible with the same time in laboratory. However, we are making plans to introduce some laboratory due to the desire for that practice in the training of high-school teachers who must give that type of
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work. It is our intention to keep the laboratory work to as small a quantity as is possible. If all the time is given to the laboratory in the first year, very little ground can be covered. I think our major students are much better off by not having that first-year work. It is possible that the teachers for high school need it. It mav be desirable for the ordinarv "arts" studegt. If it were not for the teachers and the desire to make our work uniform with other universities, I feel sure that we would not consider changing to the laboratory. We are forced to the conclusion that the individual laboratory method is not functioning, a t the present time, as its proponents anticipated. This failure may be due t o teacher weakness in administering the method, iuadaptability of the method to the abilities of our students, or-to a combination of both these factors. May it not be possible that a solution will be found in the European plan as was represented in this country by Indiana University? Should not the use of a laboratory by beginners in chemistry be the coveted privilege of the competent student rather than a universal requirement that is a t once both distasteful and ineffective for the lessfavored majority? Literature Cited (1) Committee, GORDON.Chairman, "Correlation of High-School and College Chemistry," J. Cnem. E ~ u c . 4,640-56 , (May, 1927). (2) Symposium, "What Are Our Objectives in TBaching Chemistry?"ibid., 2,971-97 c (Nov.. 1925). (3) S m m , H. R., "Objectives in Teaching Chemistry," ibid., 2, 585-7 (July, 1925). (4) C o m s o ~ ,"Educational Aims in Teaching Elementary Chemistry," ibid., 6, 1120-5 (June, 1929). (5) FRANX,"Teaching First-Year Chemistry," J. 0. Frank. Oshkosh, Wisconsin, 1926, pp. 19 and 60. (6) SMITHAND HALL,"The Teaching of Chemistry and Physics in the Secondary School," Longmans, Green & Co., New York City, 1919, p. 87. (7) PERSING,"Present Specific Objectives in High-School Chemistry," J. CHEM. EDUC.,6, 195G78 (Nov., 1929). (8) HEssLER, "What Chemistry Should Every Adult American Know?" ibid.. 4 1494 (Dee., 1927). (9) JACKSON, "What Sort of Chemistry Should Be Taught in the High School?" ibid., 4, 65 (Jan., 1927). (10) WILEY, "An Experimental Study of Methods of Teaching High-School Chemistry," J. Educ. Psychol., 9, 181-98 (1918). "A Study of the Comparison of Different Methods of Laboratory (11) CARPENTER, Practice an the Basis of Results Obtained on Tests of Certain Classes in HighSchool Chemistry," J. CHEM.EDUC.,3, 798-805 (July, 1926). "Measurable Outcomes of Individual Laboratory Work in High-School (12) HORTON, Chemistry," Teachers' College, Columbia University, 1928. L Effectivenessof the Lecture-Demonstration and Individual (13) A ~ E "Comparative Laboratory Method;' J. Educ. Research, 13,355-65 (May, 1926).
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NASHAND PHILLIPS,"A Study of the Relative Value of Three Methods of Teaching High-School Chemistry," J. Educ. Research, 15, 371-9 (May, 1927). Pucrr, "Comparison of Lecture-Demonstration and Individual Laboratory Methods of Performing Chemistry Experiments," High-Sch. Teacher, 3, 184-7 (1927). KNOX,"The Demonstration Method versus the Laboratory Method of Teaching High-School Chemistry," Sch. Re.,35,37646 (May, 1927). WALTER."The Individual Laboratory Method of Teaching Physics When No Printed Directions Are Used," Sch. Sci. Math., 30,42932 (Apr., 1930). JOHNSON. "A Comparison of the Lectwe-Demonstration Group Laboratory Experimentation, and Individual Laboratory Experimentation Methods of Teaching High-School Biology,". I. Educ. Research, 18, 103-11 (Sept., 1928). MCGAUGHY, "The Fiscal Administration of City School Systems," The Macmillan Company, New York City, 1924, p. 72. NOLL."Laboratory Instruction in the Field of Inorganic Chemistry," University of Minnesota Press, Minneapolis. 1930, p. 112. BAGBY."The Correlation of Laboratory and Classroom Work in the Teaching of High-School Chemistry," J.Educ. Research, 19,33640 (May, 1929). PARRA N D SPENCER,"Should Laboratory or Recitation Have Precedence in Teaching of High-School Chemistry?" J. CHEM.EDUC.,7,57146 (Mar., 1930). Cheirnan, "Recitation or Laboratory First," ibid.. Committee. GREENLAW, 7, 1355-9 (June, 1930). DOWNING, "Methods inscience Teaching," I. H i g h Educ., 2, 320 (June, 1931). RIEDEL,"The Present Status of the Controversy Demonstration versus Laboratory Method." Gen. Sci. Quart., 9,246-54 (May, 1927). WILES,':The Value of the Lecture-Table Demonstrationin theTeachingof Chemistry," J. CHEM.EDUC.,5,110+11 (Sept., 1930). DAvrSoN, "Lectures and Lecture E,xperiments," &id., 7, 1305-9 (June. 1930). EHRET,"Teaching Inorganic Chemistry to Thousands," ibid., 7, 322 (Feb. E 1930). (29) RAKESTRAW, "The Function and Limitations of Lecture Demonstrations," ibid., 6, 1886 (Nov., 1929). (30) GERARD,"An Adventure in Education," I. Higher Educ., 1, 193 (Apr., 1930). (31) REED. "High-School Chemistry Demonstrations," J. CHEM.EDUC.,6, 1905-9 (Nov., 1929). (32)' Anonymous, "High-School Laboratories Are Waste," School, 40, 916 (Aug. 29, 1929). (33) GOOD,"Research in Secondary School Methods," I. Educ. Research, 22,20 (June, 1930). (34) BOWERS,"The Conduct of Laboratory Work in Elementary Chemistry," Sch. Sci. Math., 25, 828-32 (Nov., 1925). (5.5) SMITH,H. R., "Some Fundamentals of Laboratory Instruction," J. CHEM.EDUC., 4, 359 (Mar., 1927). (36) VANHORNE,"The Lecture-Demonstration Method in High-School Chemistry." ihid., 7, 110, 115 (Jan., 1930). (37) CLARKE,"Minimum Essentials of Laboratory Technic," ibid., 4, 1009 (Aug., 1927). GUY, Discussion, ibid., 4, 1008 (Aug., 1927). (38) (39) LUCASSE,"The Possible Over-Emphasis of Laboratory Instruction in Higher Institutions," ibid., 5,142-50 (Feb., 1928). (40) TIMM, "An Experiment in Chemical Education a t Yale," ibid., 6, 1316-20 (JulyAug., 1929).
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BAWDEN. "The New Introductory Chemistry. Part 11," ibid., 6, 2033-7 (Nov., 19291~
WEND+, "The Problem of the One-Year Course in Chemistnr for the General Student." ibid.. 8,276 (Feb.. 1931). N ~ c x o ~"Getting s, the Student to Use His Own Intellect," Science, 44,153 (Aug, 7, 1931). TILDSLEY, "Teaching Science as a 'Way of Life,'" Bulletin of High Points, 10, 84 (1928); cj. J. EM. EDWC.,8, 670-8 (Apr., 1931). DowNINo, "Individual Laboratory Work versus Teacher Demonstration," Gen. Sci. Quart., 11, 96-9 (Jan., 1927). PIETEXS,"Chemistry and Physics in the Dutch Secondary School," J. C ~ M . 3,809, 810 (July, 1926). EDWC., D~swrrENs,"The Teaching of Chemistry in the Schools and Institutes of France," ibid.. 7,1544 (July, 1930). D ~ W ~ H E R"The T Y , Elementary Chemistry Courses a t Princeton," ibid., 5, 851 (July, 1927).
